This International Standard specifies six methods for authenticated encryption, i.e. defined ways of processing a data string with the following security objectives:- data confidentiality, i.e. protection against unauthorized disclosure of data,- data integrity, i.e. protection that enables the recipient of data to verify that it has not been modified, - data origin authentication, i.e. protection that enables the recipient of data to verify the identity of the data originator.All six methods specified in this International Standard are based on a block cipher algorithm, and require the originator and the recipient of the protected data to share a secret ke